This requires 80 stars. Only Mario can enter. Other characters must do a glitch by slide kicking on the second step, sometimes they appear outside the castle and lose a life. If done correct they can also defeat the final Bowser and beat the game with as little as 50 stars.

To get into this stage, the player requires 70 stars to solve the mystery of the endless stairs and needs to have beaten Bowser in the Fire Sea. This is the final, biggest, and most difficult level of them all. If you are ready, it's time to confront Bowser in a final battle!

When you enter Bowser in the Sky, there will be no message, similar to the second level. Do a triple jump on to the first three platforms and jump onto the sliding blue rock. Afterwards, run quickly across the tilting pathway, and run up the slant. Kill the Goombas and leap onto the spinning platform. There’s a 1-UP inside the box. Jump onto the next spinning platform, and then the gray platform. Watch out for the Venus Fire Trap. Continue on the wooden plank and jump onto the rotating platform. Jump up and go right. Pound the “!” switch to activate the stairs. Run up the slope, but watch out for the fire blasters. Run across and down to the checkered platform with the Venus Fire Trap, hop onto the moving platform and jump over the obstacles. Next, hop onto the ground and to the spinning platforms and up the pole. Jump off the pole, run on the sliding platforms and onto the next pole. Jump off and dodge the Bob-ombs and Fire Chomp. Jump from the first rotating platform to the second and onto the gray space. Watch out for the strong winds. There’s a 1-up by the far left pillar. Good luck! Like the first two levels in the DS version, there is a switch star.

Get behind Bowser and grab his tail. Spin him slowly around by rotating the analog stick 360 degrees a couple of times. Then press to toss him a little way and run up behind him and grab him again. Repeat throwing Bowser until you get close to a mine, and let him have it. The rings of fire he creates when he stomps are easy to jump over if you stand closer to Bowser (not too close!). After you throw him into two mines, Bowser will break the platform into a star. Stand in the middle when he is doing this, and grab his tail for the final time.

When you defeat him, he gives you a star with the same effect as a wing cap/feather. This leads to the fact that there are actually 121 (151 in the DS version) stars in the game. You have, technically, beaten the game. However, you still have the opportunity to go back and continue acquiring all of the stars that you may have missed. Mario will fly and land in the castle grounds where Luigi, Yoshi, Peach, The Toads, and Wario waiting for him. Mario frees Peach from the vase glass above the door entrance, who bakes a cake for the heroes, then the player sees the credits. The game ends with the heroes, Peach and Toads waving, as Latiku flies off. The player has to restart the game. In the DS version touching the touch screen automatically takes you back to the title screen. In the original game, at the end Yoshi will be on the roof, who gives Mario 100 lives and a sparkling triple jump, and jumps to the waterfall and isn't seen until the remake.